Search for dissertations about: "Ratchetting"

Showing result 1 - 5 of 10 swedish dissertations containing the word Ratchetting.

2. 1. Modelling of cyclic and viscous behaviour of thermomechanically loaded pearlitic steels; Application to tread braked railway wheels

   Author : Ali Esmaeili; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rolling contact fatigue; plasticity; tread braking; full-scale brake rig testing; Railway wheels; finite element analyses; pearlitic steel; viscoplasticity; ratchetting; phase transformations;

   Abstract : In service, railway wheel and rail materials are subjected to high stresses and, in some cases, elevated temperatures. The high stresses are caused by the rolling contact between wheel and rail. Furthermore, heat generated from tread braking and/or sliding between wheel and rail gives additional stress due to constrained thermal expansion. READ MORE

4. 2. Combined thermal and mechanical loading of railway wheel treads. A numerical study of material response and cracking under braking conditions

   Author : Sara Caprioli; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Rolling Contact Fatigue; Ratchetting; Tread braking; Plastic deformation; Thermal cracking;

   Abstract : The scope of the thesis is prediction of the material response owing to combined thermal and mechanical loading of a railway wheel tread. The long-term objective is to improve models for prediction of surface-initiated Rolling Contact Fatigue (RCF) under the combined effect of mechanical loading due to rolling (and sliding) contact and thermal loading due to braking and/or wheel--rail friction. READ MORE

5. 3. Modelling of cyclic and viscous behaviour of pearlitic steels. Application to tread braked railway wheels

   Author : Ali Esmaeili; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Railway wheels; viscoplasticity; tread braking; rolling contact fatigue; full-scale brake rig testing; finite element analysis; plasticity;

   Abstract : Railway wheel and rail materials are subjected to very high stresses and, in some cases, also elevated temperatures. The rolling contact loading results in a multiaxial stress state with a combination of compression and shear. READ MORE

6. 4. Towards simulation-based optimisation of materials in railway crossings

   Author : Rostyslav Skrypnyk; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wheel-rail contact mechanics; plasticity; metamodel; wear; S C; Dynamics vehicle-track interaction; switches crossings; FEM;

   Abstract : Railway crossings are subjected to an intense load environment caused by the rail discontinuities needed to accommodate the passage of wheel flanges in intersecting traffic directions. This gives rise to high costs associated with repair and maintenance. READ MORE

7. 5. Wheels, Rails and Insulated Joints - Damage and Failure Probability at High Speed and Axle Load

   Author : Johan Sandström; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rail breaks; probability; railway mechanics; contact mechanics; insulated joints; defects; fatigue;

   Abstract : The thesis deals with some fatigue related problems in railway mechanics related to increased axle loads and speeds. The focus is on defects and discontinuities in the wheel--rail system that affect the risk of fatigue and fracture of railway components such as wheels, rails and insulated joints. READ MORE